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uniform mat4 ModelViewProjectionMatrix;
uniform vec2 Viewport;
uniform int xraymode;
layout(points) in;
layout(triangle_strip, max_vertices = 4) out;
in vec4 finalColor[1];
in float finalThickness[1];
in vec2 finaluvdata[1];
out vec4 mColor;
out vec2 mTexCoord;
#define GP_XRAY_FRONT 0
#define GP_XRAY_3DSPACE 1
#define GP_XRAY_BACK 2
/* project 3d point to 2d on screen space */
vec2 toScreenSpace(vec4 vertex)
{
return vec2(vertex.xy / vertex.w) * Viewport;
}
/* get zdepth value */
float getZdepth(vec4 point)
{
if (xraymode == GP_XRAY_FRONT) {
return 0.0;
}
if (xraymode == GP_XRAY_3DSPACE) {
return (point.z / point.w);
}
if (xraymode == GP_XRAY_BACK) {
return 0.999999;
}
/* in front by default */
return 0.0;
}
vec2 rotateUV(vec2 uv, float angle)
{
/* translate center of rotation to the center of texture */
vec2 new_uv = uv - vec2(0.5f, 0.5f);
vec2 rot_uv;
rot_uv.x = new_uv.x * cos(angle) - new_uv.y * sin(angle);
rot_uv.y = new_uv.y * cos(angle) + new_uv.x * sin(angle);
return rot_uv + vec2(0.5f, 0.5f);
}
void main(void)
{
/* receive 4 points */
vec4 P0 = gl_in[0].gl_Position;
vec2 sp0 = toScreenSpace(P0);
float size = finalThickness[0];
float aspect = 1.0;
/* generate the triangle strip */
mTexCoord = rotateUV(vec2(0, 1), finaluvdata[0].y);
mColor = finalColor[0];
gl_Position = vec4(vec2(sp0.x - size, sp0.y + size * aspect) / Viewport, getZdepth(P0), 1.0);
EmitVertex();
mTexCoord = rotateUV(vec2(0, 0), finaluvdata[0].y);
mColor = finalColor[0];
gl_Position = vec4(vec2(sp0.x - size, sp0.y - size * aspect) / Viewport, getZdepth(P0), 1.0);
EmitVertex();
mTexCoord = rotateUV(vec2(1, 1), finaluvdata[0].y);
mColor = finalColor[0];
gl_Position = vec4(vec2(sp0.x + size, sp0.y + size * aspect) / Viewport, getZdepth(P0), 1.0);
EmitVertex();
mTexCoord = rotateUV(vec2(1, 0), finaluvdata[0].y);
mColor = finalColor[0];
gl_Position = vec4(vec2(sp0.x + size, sp0.y - size * aspect) / Viewport, getZdepth(P0), 1.0);
EmitVertex();
EndPrimitive();
}
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